Alloy steel for metal-cutting tools



'Patented June 10, 1924.

NITED STATES I PrATENr oFFics'. 1

,nnwm scams, or'xnnwoon, AND use? a. a. Aaeisraoeie, or momma, nnw YORK.

ALLOY STEEL r03. METAL-CUTTING 30 Drawing.. Continuation of applicationSerial No. 420,432, filed October 29, 1920. This application I filedJanuary 5, 1922. Serial No. 527,228.

To all whom it may concern:

Be it known that we, EDWIN CoRNINe, a citizen of the United States, and.a resident of Kenwood, count of Albany, and State of New York, and knnor'A. E. ARM- s'rnoNo, a subject of the King of Great Britain, and aresident of Loudonville, county of Albany, and State of New York, haveinvented a new and use 1 Im rove- 1 ment in A110 Steel for Tools, ofwhic the following is a specification; a

This invention relates to alloy steel for metal cutting tools, havingproperties generally intermediate between carbon steel and high-speedsteel.

The present application is a continuation of our co-pendmgfapplicationSerial No. 420,432, alloy steel for metal cutting tools,

2 filed Oct. 29, 1920.

' For small metal cutting tools, such as drills, taps, reainers and thelike, carbon steel answers sufficiently well, takes a keen cutting edgeand produces smooth finished work, but is limited in its application,be-

cause under heat it softens and dulls rapidl fiigh speed steel, which iscommonly used for somewhat larger drills and, similar tools which haveto withstand greater heat, is not, of course, rapidly softened byfrictional heat, but, in addition to its high price, has the objectionthat the work roduced is not so smooth and well finishe ascan be .ob-

' tained by sharp edge carbon steel tools, for example,. and a subseuent separate finish-' ing operation is usua y required. For ex.-;

ample, drilled holes require finish reaming to produce satisfactorywork. Further- 0 more, in the case of ta s, for example, the

- teeth of the tap areo ten injured by the high temperatures requiredfor heat treatment of high-speed steel.

The present mventi able' properties of both carbon steel and high s p isvery stron and at til-not soften w an drawn to medium telnetalutting fand I on relates to the pro-- 46 vision of an alloy steel having thedesn' eed steel, that is, which will re-v tam a, ard, keen cutting edgeand which e same time will peratures, such as 500-700 F. The steel ofperatures as in the case of high speed steel,

so that there is fipractically no tendency for any burning o of thetips. of the teeth of taps and. similar tools during heat treatment.This steel has other features of advantage as will appear from thefollowing description.

An important feature of the invention relates to the employment ofsilicon as one of the components of the alloy. The silicon appears toserve as a sort of solvent for other components and-causes them to form76 a chemical combmation with one another roduces an alloy steel havingim-' prove properties. A secondfunction of the silicon is to raise thetransformation point of the resulting alloy, thus imparting to the alloysteel the very valuable property of hardening at relatively hightemperatures. A third function of the silicon is to enhance the. airhardening properties of the alloy. Silicon enables the chromium andmolybdenum in combination with the carbon and iron to take on atremendously enhanced air hardening property. It also which would cause;a strai ht c romium,

carbon I or chromium-moly denum-carbon steel to soften.

I According to another feature, an alloy steel is provided having asone'of its com- 05' ponents a predetermined proportion of var nadium.This alloy steel has an increased red hard property. The use of vanadiumalso creates a la to transformation, that is to y. when t e steel 15rehea ed 9.1- a

hardening, 1t is given very short period after beingquenched for a la tothe breaking down of the solid solution produced in quenching.Consequently, cutting tools made of the alloy so made can withstandoverheating of their cutting edges for limited times without destructionof their cutting ability.

According to another feature, an alloy steel is provided having as oneof its components a predetermined proportion of co-- with-the carbonandiron adds to the hardness and improves other desirable physicalqualities. Chromium in combinationwith the molybdenum and carbon addsmaterially to the air hardening edect of such. combination.

One example of a composition for an alloy steel in accordance with thepresent invention is as follows:

Percent. Carbon .50 Chromium 1.50 Molybdenum l .Manganese All) SiliconVanadium .75 Cobalt approximately l Balance iron with small amounts ofphosphorus and sulfur.

Tn; order to harden this alloy it is heated as quickly as possible tosubstantially 1900" 181, without quenching in oil or water. riations inmanganese in this alloy will require inverse variations in thetemperature to which the alloy is if the manganese is increased to.l%theteml500- F, while if the manganese is increased to 1.5% thetemperature should be reduced to substantially 14:50 F.

Another example of an alloy made in accordancewith the present inventionis of about the following composition:

. Percent. Carbon l Chromium 2 Molybdenum 2 Manganese fi -.f. All)Silicon, 1 Vanadium 1 Cobalt .1

Balance iron with small-amounts of phosphorus and the quality of havingheated for example,

In order to harden this alloy it should be heated as quickl as possibleto substantially 1800 R, an quenched in oil or water. Variations inmanganese require Variations in the heat treatment temperature as in thepreceding example.

A third example of an alloy made in accordance with the presentinvention is of about the following composition:

, Per cent. Carbon 1.50

Chromium 2 Molybdenum a 2 Manganese .40 Silicon 2 Vanadium .50 Cobalt 2Per cent. Carbon .50 Chromium l0 Molybdenum 5.7 5 Manganese .40 Silicon2.5 Vanadium 2 GObfilll 2 Balance iron with small amounts of phosphorusand sulfur.

In the heat treatment of this alloy heat should be applied until thealloy has a temperature of substantially 2100? F. The alloy should thenbe cooled in-the air. This alloy may be cast for use in forming cuttingtools.

More'or less variation is possible without any substantial detriment tothe desirable are obtained with varying quantities of the severalcomponents within substantially the following range:

Per-cent.

. This represents a but good results may be obtained with smallerproportions of some of the alloy com erature should be changed tosubstantially qualities 0f h material and gmfl msulls' r25 Balance; ironwith small amounts of phosphorus and sulfur. o about the outside limits,

' ponents, with composition about as follows:

carbon .252%, molybdenum .502%, silicon .50-2%, chromium .50-2%,vanadium up to 1%, manganese up to 1%, cobalt up to 1%, and the balanceprincipally iron.

We have found that good results are obtained with heat treatment ofalloys made in accordance with the present invention, which consists ofheating the alloy to a temperature of approximately 1800 F., in as short.a time as possible, after which the "alloy may be air hardened orquenched in i are increased, The as; Wil

oil or water. It is preferably not held atthis temperature more than. ahalf-minute or so longer than necessary to heat the piece throughout.

Another alloy steel may comprise, for example, components withinsubstantially the following range:

. Per cent. Carbon .25- 2 Molybdenum .50- 5. Silicon .50-2.5 Chromium.50-10 Vanadium .25- 2 Manganese 0- 1. 5

Balance-iron with small amounts of phosphorus and sulfur. Heat treatmentsubstantially as given for previously described alloy steels. r Thecobalt steel may comprise, for exam le, components wit in substantiallythe fol owing range:

' P61 cent.

Carbon .25- 2 Molybdenum .50- 5.75 Silicon .50- 2. 5 Chromium 350-10 Mananese 0- 1.5

Coba t .25- 2 Balance iron with small amounts of phosphorus and sulfur.

Another modification com rises com-' ponentswithin substantially t efollowing range;-

- x Per cent.

Carbon .25- 2. Molybdenum 50- 5. 75 Silicon .50- 2. 5 i Chromium .50-10Manganesenn 0- 1.5

becomes quite easy to machine when properly annealed. There is verylittle tendency for this alloy combination to move, that is to say, toexhibit tendenc to warp-- ing, or other malformation upon eating up andquenching, which is a feature of cat advantage in heat treatment oftools. The characteristic grinding spark given off in grinding articlesmade ofour improved alloy steel, which does not contain tungsten, ismarkedly different from the tun ten colored spark. This is 'afeature 0marked advantage both in manufacture and use, as this alloy steel can bereadily distinguished from high speed steels by observation of the sparkproduced upon grinding. The fore-. going applies whether the alloy steelis in the annealed or hardened state.

We claim:

1. As anew com osition' of matter, an alloy steel of analys1s havingsubstantially the following range: carbon .25-2%, chromium .50-10%,molybdenum .50-5.75%,

silicon 50-25%, vanadium 0-2%, manganese 0-1.5%, cobalt 0-2%, and theprincipal part of the remainder iron;

2. Metal cutting tools made from alloy steel as claimedin claim 1.

3. Drills for drilling metal made from alloy steel as claimed in claim1.

4. As a new composition of matter, an

alloy steel of analysis having substantiallythe following range: carbon.25-2%, molybdenum .50-5.75%, silicon 50-25%, chromium 50-10%, vanadium.25-2%, manganese O-1.5%, and the principal part of the remainder iron.v

5. Metal cutting tools made from alloy steel as. claimed in claim 4.

6. Drills for drilling metal made from alloy steel as claimed in claim4.

7. As a new composition of matter, an

alloy'steel of analysis having substantially the following range: carbon.25-2%, molybdenum .505.75%, silicon .50-'-2.5%, chromium 50-10%,manganese 0-1.5%, cobalt .25-2%, and the principal part of the remainderiron.

8. Metal cutting tools made from alloy steel as claimed in claim 7.

9. Drills for drilling metal made from alloy steel as claimed in claim7.

1.0. As a newcomposition of matter, an alloy steel of analys1s havingsubstantially the following range: carbon .25-2%, molybdenum .50-5.7 5%,silicon .50-2.5%, chromium 50-10%, manganese 0-1.5%, and the princi a1part of the remainder iron.

11. etal cutting tools made from alloy steel as claimed in claim 10.

12. Drills'for drilling metal made from alloy steel as claimed -in claim10.

13. 'Anair hardening alloy steel ada ted to withstand temperatures ofabout 500- 00 F., without material softening, of analysis {5 I moooio'ivilli'iii substantially the following mmac: l5. Drills for drillingmelol medic Emmi carbon .25-2%, chromium Jill-2%, molylo alloy steel asclaimed in claim 13.

mum .502%, Silicon .502%, vanadium up to 1%, mam onese up to 1%, cobaltup to names hereto. 6 1%, and; the mlonce principoll iron.

' ll. Metal cutting tools mace fromolloy steel as claimed in claim 13.

PERCY A. E. ARMSTMlNG. EDWIN CURNIING,

In witness whereof, We hove signed om?" W V

